JPS6315156B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides multicolor printing (including overlapping printing) on the outer surface of the body of a cylindrical container using an ink transfer roll.
Concerning how to do.

(Prior art and its problems) It is known to perform multicolor printing on the outer surface of the body of a cylindrical container, such as a synthetic resin container or a metal can, and synthetic resin containers with multicolor printing are known. and metal can bodies are also seen on the market.

There are two types of cylindrical cans with multicolor printing on the outside: cans that are printed with different color inks without overlapping each other, and cans that are printed with different color inks that are partially overlapped.

An example of the former type of printing is shown in FIG. Figure 1 shows only the can body unfolded, with white paint dry-baked as the base U, red (W),
Green (X), yellow (Y), and blue (Z) inks are printed, all of which are completely separated without overlapping each other.

An example of the latter is shown in FIG. Base U′ is white,
W′ is red, X′ is green, Y′ is yellow, and Z′ is blue ink. FIG. 3 shows a - cross section of FIG. 2. Part of W′ is covered by X′, and part of X′ is
It is covered by Y′ and a part of Y′ is covered by Z′.
This polymerized portion has a color that is influenced by the color of the upper layer and the color of the lower layer.

The present applicant has developed the following technology as a multi-color printing method that can perform both overlapping and non-overlapping printing (Japanese Patent Application No. 149008/1983, Japanese Patent Application Laid-open No. 1983-1999).
−72958). A specific example of this technique will be explained with reference to FIG.

In the figure, reference numeral 2 denotes a rotary disk which rotates the mandrel 10 with the can body A sent from the can body supply path (not shown), and the ink transfer rolls 33 above and below adjacent to it. , 43. Reference numeral 11 denotes an upper printing section where the can body A mounted on the mandrel 10 advances (revolutions) due to the rotation of the rotating disk 2 and receives ink from the upper ink transfer roll 33 while being transported; This is the lower printing section where ink is transferred from the lower ink transfer roll 43. 3
0a is a first ink transfer roll that transfers the first ink to the upper transfer roll 33, and 30b is a second ink transfer roll.

31 is the first adhered ink adhering to the first ink transfer roll, and 32 is the first area 13 of the ink transfer roll 33 from the first transfer roll 30a.
This is the first transfer ink transferred to No. 2. The first zone 132 is a zone of the outer circumferential surface of the ink transfer roll 33 with a length in the circumferential direction of the outer circumferential surface equal to the outer circumferential length of the can body. 1 adhered ink is transferred. Generally, when ink is pressed between two rolls and both rolls are rotated at a constant speed while being separated from the pressed area, an ink layer of approximately equal thickness remains on both rolls.

Now, when the transfer roll 33 has rotated and completed passing under the second ink transfer roll 30b (at this time, the first area 132 has reached the point 132'), the second adhesion of the roll 30b is completed. ink 34
is transferred to the second area 135 of the roll 33.
The second transfer ink is indicated at 35. The second area 135 is divided into 1 by rotation of the ink transfer roll 33.
32' is a region adjacent to and having the same length as the first region and extending in the circumferential direction of the roll 33. These first and second sections are both equal to the outer circumferential length of the can body (indicated by l in FIG. 2).

These two ink-transferred areas 132,1
35 advances further and comes into pressure contact with the can body A that has been transferred together with the rotating disk 2. The starting point is indicated by 50. This is also the starting point of the upper printing section 11, and when the center of the can body A reaches this starting point 50, the tip of the transfer ink 32 on the first area 132 of the transfer roll 33 comes into contact with the outer surface of the barrel of the can body A. do.
The can A continues to rotate (revolution) together with the disc 2 while being in pressure contact with the roll 33, and reaches an intermediate point 55 between the start point 50 and the end point 51 of pressure contact, and ends the pressure contact with the first area ( The first zone is equal to the outer circumference of the can body). At the same time, pressure contact is started with the tip 37 of the second section (which is also the rear end of the first section). Thus, while the can body A revolves from the starting point 50 to the intermediate point 55, the upper ink transfer roll 33 moves towards the leading edge 36 of the first section.
4 (the first area is 132 The can body A is rotated by one revolution, and the first transfer ink 32 in the first area is transferred to the body of the can body A. 32'' is transferred to the body of the can body A after the transfer is completed. Note that this is the remaining ink adhering to the roll 33. The can body A then moves from 55 to the end point 51 in the second section of the upper ink transfer roll (the second section 135 has now moved to the position 135').
Transfer ink 35' is transferred from upper ink transfer roll 33.

The can body A further revolves and is printed by the lower ink transfer roll 43. This lower transfer roll 43 is provided in front of the upper ink transfer roll 33 in the forward direction of the travel path of the can body A, and 40a and 40b are third and fourth ink transfer rolls, respectively, and these configurations are as follows: The function is upper transfer roll 3
3. Since it is the same as that of the first and second ink transfer rolls, detailed explanation will be omitted, but 41 and 44 are as follows.
42 and 45 are the adhering ink of the third ink transfer roll 40a and the fourth ink transfer roll 40b, respectively, and 42 and 45 are the third and fourth areas 142 and 14 of the transfer roll 43.
These are the third and fourth transfer inks transferred to No. 5. As in the case of the first and second zones, the third zone and the fourth zone have the same length as the outer circumferential surface of the can body, and are adjacent to each other. 52 and 53 are the start and end points of the lower printing section 11', respectively, and correspond to the aforementioned points 50 and 51. However, regarding the upper transfer roll 33, the can body A has been described in a state where only the first transfer ink has been transferred, but regarding the lower transfer roll, the can body A' rotates twice, and both the third and fourth areas are transferred. The difference is that it is shown in the state where it has finished contacting (142'', 145').

Upper ink transfer roll 33 in upper printing section 11
The can A', which has received the first and second ink transfers from the lower printing section 11', further revolves and receives the third and fourth transfers from the lower transfer roll 43 in the lower printing section 11', as in the upper printing section 11. The ink is transferred.
The can is indicated by A''.The can then continues to revolve, being removed from the mandrel and ejected through a discharge channel into a drying and baking oven.

Since the method of this specific example is particularly effective when applied to overcoating, this case will be explained.
Overcoating is possible by manipulating the viscosity of the ink, and other than that, the explanation for non-overcoating can be used as is, so I will avoid repeating the explanation and only point out the main points.

In order to overcoat ink, such as overcoating a portion of the second transfer ink on top of the first transfer ink, the viscosity (here, viscosity) of the first transfer ink that has been transferred to the can barrel must be means "tack value".
The viscosity of the second transfer ink that is transferred later (i.e. on top of the first transfer ink) must be lower than that of the second transfer ink (hereinafter the same). The reason may be as follows.

First, when the can body and the ink transfer roll are brought into pressure contact to transfer the ink on the transfer roll to the can body,
The thickness of the transferred ink layer is approximately 1/2 the thickness of the ink layer on the transfer roll (as described above). Then, on top of the transferred ink in its undried state,
When the transfer roll with the next ink is brought into pressure contact,
That is, when there are two types of undried ink between the can body and the next transfer roll, the can body and the transfer roll rotate while rolling in contact, and the can body and the transfer roll gradually separate from the pressure contact state. Then, the layer of ink with lower viscosity of the two types of ink cracks. Therefore, when the viscosity of the ink that was transferred first to the can body is lower than the viscosity of the next ink, the layer of ink that was transferred first is split into two, and 1/2 of the layer of ink that was transferred first is left in the can body. layer remains, and the transfer roll contains all of the next ink and 1/2 of the ink layer previously transferred to the can.
2 layers are transferred from the can body, while when the viscosity of the earlier ink is higher, the later ink is transferred onto the earlier ink of the can body, 1/2 layer is transferred and superimposed on the can body. You will be able to print. Therefore, when overcoating four colors, it is essential to increase the viscosity in the following order: viscosity of first transfer ink> viscosity of second transfer ink> viscosity of third transfer ink> viscosity of fourth transfer ink. The viscosity of the third and fourth transfer inks, which is a requirement, is quite low, and when the ink is transferred between the ink mixing roller, transfer roller, and transfer roller, the ink will be scattered and the can body or mandrel may be damaged. There is a risk that it may adhere to the can body and stain the can body.

(Object of the Invention) The method of the present invention is an improvement on the above-mentioned multicolor printing method, and is a method aimed at reducing the above-mentioned ink scattering.

(Structure of the Invention) In detail, the method of the present invention is a method in which the outer surface of the body of a sideless seamed cylindrical container being transported is sequentially rolled and rotated in pressure contact with a plurality of ink transfer rolls to perform multicolor printing on the outer surface of the body. , transferring a first ultraviolet curable ink from the first ink transfer roll to a first area of the outer circumferential surface of the upper ink transfer roll, the circumferential length of the outer circumferential surface being equal to the outer length of the can body; the first section with a length equal to the first section in the circumferential direction;
A second ultraviolet curable ink having a different color from the first ink is transferred from the second ink transfer roll to a second area adjacent to the area, so that a second ultraviolet curing ink having a different color from the first ink is transferred from the two or more ink transfer rolls to the outer peripheral surface of the ink transfer roll one after another. A different color UV curing ink is transferred to the ink transfer roll to which this ink is transferred.
The outer surface of the container body is pressed against the outer surface of the container body by the same number of ink transfer rolls and rotated to transfer each ultraviolet curing ink from the ink transfer roll to the outer surface of the container body, and then transferred to the outer surface of the container body. After the ultraviolet curing ink is irradiated with ultraviolet rays, the ink to be transferred and ink of a different color are transferred from the upper transfer roll to the container body from the lower transfer roll.

This is a multicolor printing method for cylindrical containers.

(Function) In the present invention, the ink transferred from the upper ink transfer roll onto the outer surface of the container body is an ultraviolet curing ink, and after this ultraviolet curing ink is transferred onto the outer surface of the container body, ultraviolet rays are irradiated to cure the ultraviolet curable ink. After increasing the viscosity of the ink, the ink, which is a different color than the UV-curable ink, and in the case of overlapping printing, the ink that overlaps the UV-curable ink is transferred from the lower ink transfer roll onto the outer surface of the container body. The viscosity of the ink transferred from the lower ink transfer roll need only be lower than the viscosity of the ultraviolet curable ink, which has been increased by ultraviolet irradiation. Therefore, in the conventional method, an ink with a considerably low viscosity must be used. Since it is possible to use an ink whose viscosity is not so low as to be transferred from the lower ink transfer roll, the ink is less likely to scatter during printing.

(Example) A specific example of the method of the present invention will be explained with reference to FIG.

This specific example is the first in the multicolor printing method described above.
The transfer ink 32 and the second transfer ink 35 are UV curable inks, and the upper printing area 1
1 (UV irradiation devices for can bodies are well known). It differs from the multicolor printing method described above in that it is cured to a certain extent.

That is, the can body that has received the first transfer ink and the second transfer ink from the upper ink transfer roll 33 in the upper printing area 11 is irradiated with ultraviolet light from the ultraviolet irradiation device during the subsequent revolution, and the ink is transferred to the can body. is cured to at least a non-stick surface, and third and fourth transfer inks are transferred from the lower ink transfer roll 43 onto the cured ink in the next lower printing area 11'. The first and second transfer inks on the can body have been cured to the extent that their surfaces are not sticky, and the viscosity of these inks has increased, so it is not possible to overprint on top of the first and second transfer inks. In this case, the third transfer ink can be overcoated with an ink of lower viscosity than this increased viscosity.

When the ink transferred from the upper ink transfer roll to the can body is not irradiated with ultraviolet rays, in order to transfer the ink from the lower ink transfer roll to the can body, the viscosity of the ink must be lower than that of the ink transferred to the can body. The things that must be done are as described above.

(Effects of the Invention) When using the method of the present invention, even if the viscosity of the third transfer ink is high, it is possible to apply multiple coats compared to the case where ultraviolet rays are not irradiated, and therefore, staining of the container due to ink scattering is reduced. It has the effect of

In addition, the range of ink viscosity selection is widened, which has the effect of making it easier to adjust the ink viscosity.

Furthermore, there is also the effect that the drying time after four-color printing is short.

Note that the third and fourth transfer inks are not limited to ultraviolet curing inks, but may also be thermosetting inks.

[Brief explanation of the drawing]

Figure 1 is a developed view of an example of a multi-color printed can body with non-overlapping coating, Figure 2 is a developed view of an example of a multi-colored printed can body with overlapping coating, and Figure 3 is a cross-sectional view taken along the line shown in Figure 2. (The thickness is exaggerated) and FIG. 4 are schematic diagrams showing an example of the method of the present invention. In Figure 4, A: Can body, A': Can body to which the first and second inks have been transferred, A'': Can body to which the third and fourth inks have been transferred, 2: Rotating circle for can body transfer. Board, 11:
Upper printing section, 11': Lower printing section, 33: Upper ink transfer roll, 43: Lower ink transfer roll, 30a, 30b, 40a, 40b: Ink transfer roll, 132: First section, 135: Second section, 142 :3rd area, 145:4th area, 3
2: first transfer ink, 35: second transfer ink, 4
2: Third transfer ink, 45: Fourth transfer ink.

Claims (1)

[Claims] 1. A method for performing multicolor printing on the outer surface of a body of a side-less seamed cylindrical container by sequentially rolling and rotating the outer surface of the body of a side-less seamed cylindrical container in pressure contact with a plurality of ink transfer rolls during transport, comprising: an upper ink transfer roll; transferring a first ultraviolet curable ink from a first ink transfer roll to a first section of the outer circumferential surface of the outer circumferential surface having a circumferential length equal to the outer circumferential length of the container body; the first area with a length equal to the first area;
from the two or more ink transfer rolls onto the outer peripheral surface of the upper ink transfer roll such that a second ultraviolet curable ink of a different color than the first ink is transferred from the second ink transfer roll to a second area adjacent to the area; One after another, UV curing ink of a different color is transferred, and the outer peripheral surface of the container body is pressed against the upper ink transfer roll to which the ink has been transferred, by rolling and rotating the same number of ink transfer rolls to transfer the upper ink. Each UV-curable ink is transferred from the roll to the outer surface of the container body, and then the UV-curable ink transferred to the outer surface of the container body is irradiated with ultraviolet rays, and then the transferred ink and a different color ink are transferred from the upper ink transfer roll to the lower ink. A multicolor printing method for cylindrical containers characterized by transferring from a transfer roll to the container body. 2 The viscosity of the second ultraviolet curable ink is lower than the viscosity of the first ultraviolet curable ink, and
A multicolor printing method for a cylindrical container according to claim 1, wherein the ultraviolet curable ink is printed over the outer surface of the container body.